Derivatives of 1,6-phenazinediol 5,10-dioxide

ABSTRACT

6-Substituted derivatives of 1-phenazinol 5,10-dioxide which possess broad spectrum anti-microbial activity are disclosed.

United States Patent Leimgruber et a].

[451 July 18,1972

DERIVATIVES OF 1,6-PHENAZINEDIOL 5,10-DIOXIDE Willy Leimgruber,Montclair; Manfred Weigele, North Caldwell, both of NJ.

Assignee: Hoffman-La Roche lnc., Nutley, NJ.

Filed: April 2, 1970 Appl. No.: 25,297

Inventors:

US. Cl. ..260/267, 260/247.5 R, 424/248,

424/250 Int. Cl. ..C07d 51/80 Field of Search ..260/247.5, 267

Primary Examiner-Nicholas S. Rizzo Assistant Examiner-Anne Marie T.Tighe Attorney-Samuel L. Welt, Jon S. Saxe, Bernard S. Leon. Gerald S.Rosen and R. Hain Swope [57] ABSTRACT 6-Substituted derivatives ofl-phenazinol 5, l O-dioxide which possess broad spectrum anti-microbialactivity are disclosed.

9 Claims, No Drawings 1 DERIVATIVES OF 1,6-PIIENAZINEDIOL 5,10-DIOXIDEDESCRIPTION OF THE INVENTION i have the added advantage over the parentantibiotic of possessing better solubility properties.

The novel derivatives to which the invention relates are selected fromthe group consisting of compounds represented by the formula HO Iwherein R, signifies hydrogen or lower alkyl; and R signifies hydroxy,lower alkoxy, amino, mono-lower alkylamino, di-lower alkylamino,hydroxy-lower alkylamino, [di-lower alkylamino-lower alkyllamino or Zwherein Z signifies a 5 or 6 membered saturated heterocyclic ringcontaining a nitrogen atom and at most one further hetero atomconsisting of oxygen.

As used herein, the term lower alkyl" either alone or in combinationdenotes straight or branched chain saturated hydrocarbon groupscontaining from one to seven carbon atoms inclusive, such as methyl,ethyl, propyl, isopropyl, butyl, pentyl, hexyl and the like, with groupscontaining from one to four carbon atoms being preferred. The term loweralkoxy designates straight or branched chain alkoxy groups containingfrom one to seven carbon atoms, preferably from one to four carbonatoms, such as methoxy, ethoxy, propoxy and the like.

In a preferred aspect, when R signifies Z, S being defined as above, theheterocyclic ring is saturated and represents a member selected from thegroup consisting of morpholino, piperidino, and pyrrolidino.

Representative of the compounds of formula I are:

6-hydroxy-l-phenazinoxyacetic acid 5,10-dioxide ethyl ester 6-hydroxy- 1-phenazinoxyacetic acid 5 l O-dioxide 6-hydroxy-a-methyll-phenazinoxyacetic acid 5,1 O-dioxide ethyl estero-hydroxy-a-methyl-[-phenazinoxyacetic acid 5,10-dioxide6-hydroxy-a-ethyll -ph'enazinoxyacetic acid 5 I O-dioxide ethyl ester-hydroxy-a-ethyl-l-phenazinoxyacetic acid 5,l0-dioxidefi-pyrrolidinylcarbonylmethoxy l -phenazional 5 l O-dioxide6-hydroxy-N-( 2-hydroxyethyl l -phenazinoxyacetamide 5 l O-dioxide 6-hydroxy-N-methyll -phenazinoxyacetamide 5,10-dioxide 6-hyd roxy-N-(3-dimethylaminopropyl l -phenazinoxyacetamide 5,10-dioxideo-hydroxy-l-phenazinoxyacetamide 5,10-dioxide A preferred class ofcompounds falling within the scope of formula I are those wherein Rsignifies hydroxy or lower alkoxy, i.e., compounds of the formula (T) OCHC\ @N OR:

T/ HA) 0 I8 wherein R, is as described above and R, signifies hydrogenor lower alkyl. The compounds of formula la above are preferred becauseof their interesting level of biological activity.

Another class of compounds preferred because of their interestingbiological activity and falling within the scope of the presentinvention are those wherein R, signifies hydrogen and R signifies amino,mono-lower alkylamino or di-lower alkylamino, i.e., compounds of theformula wherein R, and R each independently signify hydrogen or loweralkyl. Most preferred of the compounds of fomlula lare:

o-hydroxy-l-phenazinoxyacetic acid 5,10-dioxide ethyl ester 6-hydrOxyl-phenazinoxyacetic acid 5,1 O-dioxide o-hydroxy-a-methyll-phenazinoxyacetic acid 5 l O-dioxide ethyl ester o-hydroxy-a-methyll-phenazinoxyacetic acid 5 l O-dioxide o-hydroxyl -phenazinoxyacetamide5, l O-dioxide 6-hydroxy-N-( B-dimethylaminopropyl l-phenazinoxyacetamide S, l O-dioxide The compounds of formula 1 abovemaybe prepared following a variety of procedures. The choice ofprocedures will depend upon the nature of the R, and R substituents tobe introduced into the phenazinol molecule.

For example, the compounds of formula I wherein R signifies a loweralkoxy group can be prepared using conventional alkylating techniques.This alkylation procedure, which results in the preparation of the esterderivatives, is preferably carried out in two stages. In the firststage, the known compound l,6-phenazinediol 5,10-dioxide (iodinin),which is used as the starting material is converted to its mono-alkalimetal salt, preferably the potassium salt. The conversion of iodinin toits alkali metal salt is accomplished by reacting iodinin with an alkalimetal base. This reaction is expediently effected in the presence of anaprotic polar organic solvent, such as hexamethylphosphon'c triamide(HMPT), dimethylformamide (DMF) and dimethylsulfoxide (DMSO), with HMPTbeing preferred. Use of an aprotic polar organic solvent is preferredsince this solvent can also be utilized in the alkylation step, thuseliminating the necessity of first isolating the iodinin salt. Suitablealkali metal bases that may be used to fonn the iodinin salt includealkali metal lower alkoxides containing from one to four carbon atoms.Preferred alkali metal lower alkoxides include the sodium and potassiumcompounds, with potassium t-butoxide being the most preferred alkalimetal lower alkoxide.

In the second stage of the alkylation process, the monoalkali metal saltof iodinin is selectively alkylated by reacting said salt with thecorresponding a-halo ester. Suitable a-halo esters for this purposeinclude ethyl bromo acetate, ethyl orbromopropionate, ethyla-bromo-n-butyrate and the like. As indicated above, this selectivealkylation of the mono-alkali metal salt of iodinin is expedientlyeffected in the presence of an aprotic polar organic solvent such asHMPT, DMF and DMSO, with HMPT being preferred. The alkylation reactionconditions can be varied. However, for convenience and optimum yieldssuitable conditions include the use of temperatures between about 10 andabout C and reaction times sufiicient to complete the reaction, usuallyfrom about i to about 24 hours. In a preferred aspect, the alkylationreaction is effected at room temperature.

in a further process aspect of the present invention, the novelcompounds of formula 1 wherein the R substituent is hydroxy may beprepared by the hydrolysis of the corresponding compounds of formula 1wherein R signifies lower alkoxy, i.e., by hydrolysis of thecorresponding ester derivatives. This hydrolysis is effected by treatingthe ester compound with an aqueous base. Suitable bases for this purposeinclude alkali metal hydroxides such as sodium hydroxide, potassiumhydroxide and the like; and alkali metal carbonates such as sodiumcarbonate, sodium bicarbonate and the like; with sodium hydroxide beingthe most preferred base. This reaction is expediently effected in thepresence of an aprotic polar organic solvent such as HMPT, DMF and DMSO,with HMPT being preferred. Temperature and reaction time are notcritical to this process aspect. Therefore, temperatures in the range offrom about to about 70 C are suitable, with room temperature beingpreferable. LikewiSe, reaction times sufficient to permit completion ofthe reaction are employed, usually from about 1 to about 24 hours.

In a further process aspect of the present invention, the novelcompounds of formula 1 wherein the R substituent is an amino group or aprimary or secondary amine may be prepared by treating the esterderivative with ammonia or the corresponding aliphatic or saturatedcyclic amine. Representative amines that may be used in this processaspect include monomethylamine, diethylamine, ethanolamine, 3-dimethylamino-propy1amine, pyrrolidine, morpholine, piperidine and thelike. Temperature and reaction time are not critical to this processaspect. Thus, temperatures between 10 and 70 C are suitable, with roomtemperature being preferred. Likewise, reaction times which permitcompletion of the reaction are employed, usually from about 1 to about24 hours.

The novel compounds of formula 1 have been found to possess broadspectrum antimicrobial activity. In particular, these compounds havedemonstrated a high level of activity against a wide variety ofbacteria, yeasts and fungi such as Streptococcur agalactiae,Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa,Moraxella bovis, Candida albicans, and Microsporum canis. The novelcompounds of this invention are particularly useful in the treatment ofanimal diseases of microbial origin. When the novel compounds of formula1 are employed in the treatment of microbial infections, they areconveniently utilized in combination with suitable pharmaceuticalcarrier materials. These compositions are formulated by uniformlydistributing the compound of formula l throughout a vehicle that ischemically compatible with the particular compound, non-inhibiting withrespect to the active ingredients and essentially non-injurious to thebody tissue under the conditions of use. When formulated intocompositions suitable for topical administration, the novel compounds ofthis invention are preferably employed in amounts ranging from about0.05 percent to about 1.0 percent by weight of the composition. Thecompounds of this invention when employed in forms suitable for topicaladministration may be utilized in varied formulations: for example, insolid formulations including finely divided powders and granularmaterials and liquid formulations including suspensions, concentrations,tinctures, slurries, aerosols, and the like. Further, they may beemployed as creams, gels, jellies, ointments, pastes, etc.

The following examples further illustrate the scope of the invention.All temperatures given are in degrees centigrade unless indicatedotherwise.

EXAMPLE 1 Preparation of 6-hydroxy-l-phenazinoxyacetic acid 5,10-dioxide ethyl ester 7.32 grams of iodinin, 450 ml of hexamethylphosphoric triamide (HMPT) and 3.9 grams of potassium tertiary butylalcoholate were placed in a flask. The reaction mixture was stirred atroom temperature for 16 hours and then 6.0 ml of ethyl bromo acetatewere added. The stirring was continued at room temperature for 3 hours.The reaction mixture was poured into 2.0 liters of ice water andextracted with 3 X 500 ml of ethyl acetate. The combined ethyl acetateextracts were washed with 500 ml of water and filtered through a mediumsintered glass funnel to break the emulsion. The combined ethyl acetateextracts were dried over magnesium sulfate and concentrated in vacuo.The residue was dissolved in CH Cl and chromatographed over 250 grams ofsilica gel to yield 6- hydroxy-l-phenazinoxyacetic acid 5,10dioxideethyl ester, m.p. l52(dec.).

EXAMPLE 2,

Preparation of 6-hydroxy-l-phenazinoxyacetic acid 5,l0- dioxide 10.5grams of 6-hydroxy-1-phenazinoxyacetic acid 5,10- dioxide ethyl ester,200 ml of HMPT and 50 ml of 5 percent aqueous sodium hydroxide wereplaced in a flask and stirred at room temperature for 5 1% hours. Thereaction mixture was poured into 2.0 liters Of ice water and acidifiedwith 10 percent aqueous HCl. The aqueous phase was extracted with CH Clseveral times. The combined organic phases were extracted with 5 percentaqueous sodium bicarbonate (approximately 1.5 liters). The basicextracts were acidified with 10 percent aqueous HCl. The mixture wasallowed to stand at room temperature for one-half hour and the solidswere then filtered with water. The solids were slurried in approximately40 ml of acetone, filtered and air-dried to yield dark red crystals of6-hydroxy-l-phenazinoxyacetic acid 5,10-dioxide, m.p. 185 (dec.).

EXAMPLE 3 Preparation of 6-hydroxy-a-methyl-1-phenazinoxyacetic acid5,l0-dioxide ethyl ester 7.32 grams of iodinin were suspended in 450 mlof HMPT. To this was added with stirring 3.9 grams of potassiumtertiary-butyl alcoholate. The stirring was continued over night. Then 6m1 of ethyl-2-bromopropionate were added and the stirring was continuedfor another 3 hrs. The reaction mixture was then poured into crushedice/water (1,200 ml). The reaction mixture was then extracted with 3 X400 ml ethyl acetate, washed with 3 X 200 ml of water, dried overmagnesium sulfate and evaporated to dryness. The residue was dissolvedin the minimum amount of dichloromethane, filtered and chromatographedover 250 grams of silica gel to yield 6-hydroxy-a-methyl-l-phenazinoxyacetic acid, 5,10-dioxide ethyl ester,m.p. 133 (dec.).

EXAMPLE 4 Preparation of o-hydroxy-a-methyl-l-phenazinoxyacetic acid5,10-dioxide 4.13 grams of 6-hydroxy-a-methy1-l-phenazinoxyacetic acid5,10-dioxide ethyl ester and ml of HMPT were placed in a flask. To thiswas added 20 ml of aqueous 5 percent sodium hydroxide. The reactionmixture was stirred at room temperature for 5 /1 hours. It was thendiluted with approximately 600 ml of water, made slightly acetic with 10percent aqueous hydrochloric acid and extracted with CH Cl The organicextracts were extracted with 5 percent aqueous sodium bicarbonate. Thebicarbonate extract was acidified with 10 percent aqueous HCl and thesolids filtered and washed with water. The desired product wasrecrystallized from acetone and the solids were filtered to yield redcrystals of 6-hydroxy-amethyl-1-phenazinoxy-acetic acid 5,10-dioxide,m.p. 208-21 0 (dec.).

EXAMPLE 5 Preparation of 6-hydroxy-a-ethyl-l-phenazinoxyacetic acid5,l0-dioxide ethyl ester 7.32 grams of iodinin and 450 ml of HMPT wereplaced in the flask. The reaction mixture was stirred at roomtemperature for 17 hours and then 6.0 ml of ethyl-a-bromo-n-butyratewere added. Stirring was continued at room temperature for 4 /2 hours.The reaction mixture was diluted with about 1,200 ml of water andextracted with 4 X 400 ml of ethyl acetate. The combined ethyl acetateextracts were washed with 250 ml of water and the entire contents of theseparatory funnel were filtered. The filtrate layers were separated andthe organic layers washed with 2 X 250 ml of water, dried over magnesiumsulfate and concentrated in vacuo. The residue was dissolved in CH Cland chromatographed over 400 grams of silica gel to yieldfi-hydroxy-a-ethyl-l-phenazinoxyacetic acid 5,10- dioxide ethyl ester,m.p. 129 (dec.).

EXAMPLE 6 Preparation of o-hydroxy-a-ethyl-l-phenazinoxyacetic acid5,10-dioxide 2.0 grams of G-hydroxy-a-ethyl-l-phenazinoxyacetic acid5,l-dioxide ethyl ester, 40 ml of HMPT and 10 ml of 5 percent sodiumhydroxide were placed in the flask. The reaction mixture was stirred atroom temperature for 5 A hours. This was then diluted with 800 ml of icewater. To this was added 20 ml of percent HCl. The precipatate wasfiltered off and washed on the filter 2 X 50 ml of water and 1 X 30 mlof methanol. The precipatate was recrystallized from acetone/chloroformto yield 6-hydroxy-a-ethyl-l-phenazinoxyacetic acid 5,10-dioxide, m.p.134l 35.

EXAMPLE 7 Preparation of 6-pyrrolidinylcarbonylmethoxyl-phenazinol5,10-dioxide 1.50 grams of 6-hydroxy-l-phenazinoxyacetic acid 5,10-dioxide ethyl ester and ml of pyrrolidine were placed in a flask. Thereaction mixture was stirred at room temperature for 3 hours. Thereaction mixture was then diluted with 400 ml of CHCl and washed with 4X 100 ml of 10 percent aqueous HCl. The reaction mixture was then washedonce with 5 percent aqueous sodium bicarbonate and once with water,dried over sodium sulfate and concentrated in vacuo. The residue wasrecrystallized from acetone to yield 6-pyrrolidinylcarbonylmethoxy-l-phenazinol 5,10-dioxide m.p. 147 (dec.).

EXAMPLE 8 Preparation of 6-hydroxy-N-(2-hydroxyethyl)- l-phenazinoxyacetamide 5,10-dioxide 1.5 grams of6-hydroxy-lphenazinoxyacetic acid 5,10- dioxide ethyl ester waresuspended in 30 ml of ethanolamine. The mixture was stirred at roomtemperature for 4 hours and then diluted with 250 ml of chloroform,washed extensively with dilute HCl and then with water. The chloroformsolution was dried over sodium sulfate and evaporated to dryness invacuo. The crystalline residue was slurried in ether and filtered togive 6-hydroxy-N-(2-hydroxy-ethyl)-l-phenazinoxyacetamide 5,10-di0xide,m.p. l52-l 55.

EXAMPLE 9 Preparation of -hydroxy-l-phenazinoxyacetamide 5,10-dioxide3.00 grams of 6-hydroxy-l-phenazinoxyacetic acid 5,10- dioxide ethylester were placed in a sealed tube. The tube was cooled in dryice/acetone and into it was condensed about 50 ml of ammonia. The tubewas sealed and allowed to come to room temperature and stand at roomtemperature over night. The sealed tube was shaken at room temperaturefor 4 hours, cooled and opened. The open tube was allowed to come toroom temperature to let the excess ammonia evaporate. The contents ofthe tube were slurried with hot CHCl repeatedly and the solids werefiltered, washed with CHCl and finally with ether to yield6-hydroxy-l-phenazinacetamide 5,10-dioxide, m.p. 175-178(dec.).

EXAMPLEIO Preparation of 6-hydroxy-N-(3-dimethylaminopropyl)-lphenazinox acetamideS l0-dioxide 500 mlligrams ofo-hydroxy-l-phenazinoxyacetic acid 5,10-dioxide ethyl ester and 5.0 mlof S-dimethylamino propylamine were placed in a flask and stirred atroom temperature for 24 hours. The reaction mixture was diluted withCHCl and washed with water until the water washes were neutral. The CHCllayer was extracted with 10 percent aqueous HCl. The combined acidextracts were made basic with sodium carbonate. The basic mixture wasextracted with ethyl acetate. The ethyl acetate extracts were washedwith water, dried over sodium sulphate and concentrated in vacuo todryness. The residue was slurried with ether and the solids werefiltered and washed with ether to yield 6-hydroxy-N-(3-dimethylaminopropyl)-l-phenazinoxyacetamide 5,10-dioxide as redcrystals, m.p. 144 (dec.).

EXAMPLE 1 l 1.0 grams of 6-hydroxy-l-phenazinoxyacetic acid 5,l0-'

dioxide ethyl ester was placed into a sealed tube. The tube was cooledwith dry ice/acetone and into it was condensed about 40 ml ofmonomethylamine. The tube was sealed and allowed to come to roomtemperature and shaken at room temperature for 1 hour. The sealed tubewas cooled and the tube was opened and allowed to come to roomtemperature to allow the excess monomethylamine to evaporate over night.The residue was dissolved in CHCl and washed with water until the waterwash was neutral. The CHCl solution was dried over sodium sulfate andconcentrated in vacuo. The residue was recrystallized from CHCl /acetoneto yield o-hydroxy-N- methyl-l-phenazinoxyacetamide 5,10-dioxide, m.p.168

(dec.).

We claim: 1. A compound selected from the group of compounds of theformula 1 (T) (I) OH C O /N\ R;

wherein R, signifies hydrogen or lower alkyl; and R signifies hydroxy,lower alkoxy, amino, mono-lower alkylamino, dilower alkylamino,hydroxy-lower alkylamino, [di-lower alkylamino-lower alkyl]-amino or Z,wherein Z signifies a 5 or 6 membered heterocyclic ring selected fromthe group consisting of morpholino, piperidino and pyrrolidino.

2. A compound of claim 1 wherein R signifies lower alkoxy.

3. A compound of claim 2 wherein R, signifies hydrogen and the loweralkoxy group is ethoxy, i.e. o-hydroxy-lphenazinoxyacetic acid5,10-dioxide ethyl ester.

4. The compound of claim 2 wherein R, signifies methyl and the loweralkoxy group is ethoxy, i.e. 6-hydroxy-a-methyl-lphenazinoxyacetic acid5,10-dioxide ethyl ester.

5. A compound ofclaim 1 wherein R signifies hydroxy.

6. The compound of claim 5 wherein R, signifies hydrogen, i.e.6-hydroxyl -phenazinoxyacetic acid 5,10-dioxide.

7. The compound of claim 5 wherein R, signifies methyl, i.e.6-hydroxy-a-methyll -phenazinoxyacetic acid 5 l O-dioxide.

8. The compound of claim 1 wherein R, signifies hydrogen and R signifiesamino, i.e. 6-hydroxy-l-phenazinoxyacetamide 5,10-dioxide.

9. The compound of claim 1 wherein R, signifies hydrogen and R signifies3-dimethylaminopropyl, i.e. 6-hydroxy-N-(3-dimethyl-aminopropyl)-l-phenazinoxyacetamide 5,10-dioxide.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT N0. 3,678,051

DATED July 18, 1972 lN\/ ENTOR(S) Willy Leimgruber and Manfred WeigeleIt is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Example 5, line 21 after "HMPT", please insert and 3.9 grams ofpotassium tertiary butyl alcoholate-.

Signed and Scaled this Eighteenth Day of October 1977 [SEAL] Attest:

RUTH C. MASON LUTRELLE F. PARKER Attesting Oflicer Acting Commissionerof Patents and Trademarks

2. A compound of claim 1 wherein R2 signifies lower alkoxy.
 3. Acompound of claim 2 wherein R1 signifies hydrogen and the lower alkoxygroup is ethoxy, i.e. 6-hydroxy-1-phenazinoxy-acetic acid 5,10-dioxideethyl ester.
 4. The compound of claim 2 wherein R1 signifies methyl andthe lower alkoxy group is ethoxy, i.e. 6-hydroxy- Alpha-methyl-1-phenazinoxyacetic acid 5,10-dioxide ethyl ester.
 5. A compoundof claim 1 wherein R2 signifies hydroxy.
 6. The compound of claim 5wherein R1 signifies hydrogen, i.e. 6-hydroxy-1-phenazinoxyacetic acid5,10-dioxide.
 7. The compound of claim 5 wherein R1 signifies methyl,i.e. 6-hydroxy- Alpha -methyl-1-phenazinoxyacetic acid 5,10-dioxide. 8.The compound of claim 1 wherein R1 signifies hydrogen and R2 signifiesamino, i.e. 6-hydroxy-1-phenazinoxyacetamide 5,10-dioxide.
 9. Thecompound of claim 1 wherein R1 signifies hydrogen and R2 signifies3-dimethylaminopropyl, i.e.6-hydroxy-N-(3-dimethyl-aminopropyl)-1-phenazinoxyacetamide5,10-dioxide.